hh_client --remove-dead-fixmes removes ALL fixmes

[ssandler]

Describe the bug
Instead of only removing dead fixmes (which don't produce a type error when removed) this command now removes all of them.

Standalone code, or other way to reproduce the problem

$ git clone https://github.com/hhvm/hhast.git
$ cd hhast
$ composer install
$ docker run -it -v $(pwd):/hhast -w /hhast hhvm/hhvm:4.153-latest bash
$ hh_client --no-load
No errors!
$ hh_client --remove-dead-fixmes
$ hh_client
...
744 errors found.

Expected behavior

Only fixmes which can be removed without introducing typechecker errors are removed.

Actual behavior

Seemingly all fixmes are removed, introducing typechecker errors.

Environment

• Operating system
  Ubuntu 18.04
• Installation method
  hhvm/hhvm on dockerhub
• HHVM Version

HipHop VM 4.153.0 (rel) (non-lowptr)
Compiler: 1647458518_157060578
Repo schema: 534e885b23eb8788358662b280cabd6799199f99

[Wilfred]

Yeah, it's removing too many fixmes in some cases and too few in others. Tracked as T125330792, we're seeing the same thing.